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231.
Autoregressive Forecasting of Some Functional Climatic Variations   总被引:4,自引:0,他引:4  
Many variations such as the annual cycle in sea surface temperatures can be considered to be smooth functions and are appropriately described using methods from functional data analysis. This study defines a class of functional autoregressive (FAR) models which can be used as robust predictors for making forecasts of entire smooth functions in the future. The methods are illustrated and compared with pointwise predictors such as SARIMA by applying them to forecasting the entire annual cycle of climatological El Nino–Southern Oscillation (ENSO) time series one year ahead. Forecasts for the period 1987–1996 suggest that the FAR functional predictors show some promising skill, compared to traditional scalar SARIMA forecasts which perform poorly.  相似文献   
232.
Shewhart's type control charts for monitoring the Multivariate Coefficient of Variation (MCV) have recently been proposed in order to monitor the relative variability compared with the mean. These approaches are known to be rather slow in the detection of small or moderate process shifts. In this paper, in order to improve the detection efficiency, two one-sided Synthetic charts for the MCV are proposed. A Markov chain method is used to evaluate the statistical performance of the proposed charts. Furthermore, computational experiments reveal that the proposed control charts outperform the Shewhart MCV control chart in terms of the average run length to detect an out-of-control state. Finally, the implementation of the proposed chart is illustrated with an example using steel sleeves data.  相似文献   
233.
This article studies majority voting over the size and location of a public good when voters differ both in income and in their preferences for the public good location. Public good provision is financed either by a lump sum tax or by a proportional income tax. We analyze both the simultaneous and the sequential determinations of the public good’s size and location. We show that, while the choice of the type of public good follows the traditional median logic, the majoritarian determination of the taxation rate need not coincide with the preferences of a median income citizen. With lump sum financing, income heterogeneity plays no role and the sequential equilibrium consists of the median location together with the public good level most-preferred by the individual located at the median distance from the median. This policy bundle also constitutes an equilibrium with simultaneous voting in the special case of a uniform bivariate distribution of individuals’ income and location. With proportional taxation, there is no policy equilibrium with simultaneous voting. We offer a complete characterization of the equations describing the sequential equilibrium in the general case and we show why and how our results depart from those most-preferred by the median income individual located at the median distance from the median. We also compare these majority voting allocations with the socially optimal one.  相似文献   
234.
We measure the past production of research articles by current members of European economics institutions. All EconLit journals are used, weighted to reflect differences in quality. Both a long (1971–2000) and a short (1996–2000) time period are considered. We also provide production indices that take into account the authors' career length. The total output of each research center is measured as well as its production per member. The focus is on 600 centers from eighteen European countries (EU 14, Israel, Norway, Switzerland, and Turkey). European centers are compared to the top sixty U.S. economics departments. Statistics regarding the concentration of article production across researchers, institutions, and countries are provided, as well as on publication habits. (JEL: A14, L11, R32)  相似文献   
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Previous research studies and anecdotal evidence portray shooting galleries as locales that place injection drug users at great risk for HIV infection, drug use and violence. Collectively, these studies highlight the need to intervene with injectors who frequent shooting galleries. However, few researchers have studied an often-forgotten risk group – women injecting drug users who frequent shooting galleries – and compared their risk behaviors to their male counterparts. To address this gap in the research literature and to evaluate the functionality of the shooting gallery as a setting for HIV prevention, we collected data on risk practices from 201 injectors (101 men and 100 women) who were recruited from eight shooting galleries in Miami, Florida. Results indicate that, compared with men, women injectors engaged in a similar variety and frequency of injection risk behaviors and had more shooting companions. While only minor gender differences were apparent, relatively few injectors – male or female – adhered to current recommendations for needle hygiene practices. Needle hygiene practices existed equally among injectors of both sexes, however very few adhered to current recommendations. Furthermore, contrary to common images of shooting galleries, use of other drugs was infrequently reported, episodes of violence or victimization were uncommon, and sexual contact almost never occurred. Operators of shooting galleries, both men and women, indicated their willingness to participate in HIV prevention efforts. Implications of these findings for HIV intervention indicate that (1) there is a great need to intervene with both men and women IDUs who frequent shooting galleries and that (2) shooting galleries can be an optimal setting for HIV prevention.  相似文献   
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The current poverty rate and the persistent poverty rate are both included in the European Union’s (EU's) portfolio of primary indicators of social inclusion. We show that there is a near-linear relationship between these two indicators across EU countries drawing on empirical analysis of EU-SILC and ECHP data. Using a prototypical model of poverty dynamics, we explain how the near-linear relationship arises and show how the model can be used to predict persistent poverty rates from current poverty information. In the light of the results, we discuss whether the EU's persistent poverty measure and the design of EU-SILC longitudinal data collection require modification.  相似文献   
240.
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